I select a free app, tap "free", tap "confirm", and get a messages that says I cannot download at this time, try again later. ...several times over the day, same thing. (I have connectivity as browser fetches web pages.)

What are the possible reasons why I cannot download free apps to my NC?

I couldn't run any apps on my new Nook Color (I was getting the "Unable to Download..." error too) until I manually installed a software update. I know this thread is old but it's one of the references that turned up in web searches as I tried to figure out the problem. For whatever it's worth, I wrote more about this: Nook Color: Unable to Download Apps.